Life jacket damage question

Canopy Locked

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Caught the Hampster on TV last night and one of his demos showed an inflatable matress freezing while being inflated with CO2. (gas cools at it expands)

This got me thinking... lifejackets are inflated by compressed CO2, would the bladder of a jacket be damaged when inflated by pulling the rip cord? Can the jacket simply be re-armed and re-packed?

Just idle curiosity..
 

Topcat47

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The adiabatic expansion of the gas will cause cooling in any environment. The rate of cooling of the gas will be greater then the conduction of heat through the lifejacket envelope into the water. Inflatable mattresses are much bigger than lifejackets, so the gas represents a much bigger heat sink. Frost forming on the surface of the mattress is caused by the failure of the air surrounding the boundary to remove cold air and replace with ambient air. Water can still freeze at the surface of the life jacket if the rate of inflation of the jacket and the volume of gas contained therein are sufficiently great.

Whether this will happen will depend upon the ambient temperature (this will be the temperature of the gas in the cylinder), the temperature of the water, the volume of gas in the cylinder and the size of the inflation venturi.
 

Leighb

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When mine inflated accidentally last season when I was trying to sort out a tangle under the foredeck it did not freeze. However an inflated lifejacket was a serious embarrassment when trying to gybe/lower the spinnaker in a 20ft dayboat /forums/images/graemlins/frown.gif

I seriously considered stabbing it with my knife, but did manage to deflate it using the little doofery on the inflation tube. I now make sure the manual inflation tag is well tucked away.
 

Scotty_Tradewind

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My crew got a drenching in the cockpit and his lifejacket inflated. He was throttled to such an extent by the tightening of the jacket on top of all his waterproofs, that we nearly stabbed it to release him as the release valve was up inside and almost impossible to get to.
What would have happened if he had gone overboard with it like that we dread to think!
 
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